Generally, the functions of a modern portable computer are no less varied than the functions of a desktop computer. A modern mobile computer is designed to be lightweight and to have various functions. For example, laptop computers, palmtop computers, personal digital assistants (PDA), and tablet personal computers all execute compute-intensive applications.
A peripheral component interconnect (PCI) interface adapter card may be replaced or inserted in a desktop computer. However, a portable computer may have restrictions with respect to space, weight, and power consumption. Accordingly, the number of extension slots which may be used in a portable computer may be limited.
A portable computer may be able to wirelessly communicate with a plurality of external apparatuses using a wireless local area network (LAN) card to compensate for such lack of extensibility.
Types of wireless LANs include, for example, Personal Computer Memory Card International Association (PCMCIA) cards, universal serial bus (USB) cards, and peripheral component interconnect (PCI) cards. A PCMCIA wireless LAN card may be provided for a notebook, wherein it is inserted in a PCMCIA card slot. A USB wireless LAN card may be connected to a USB port of a notebook computer or desktop computer, and a PCI wireless LAN card may be housed in a PCI card slot of a desktop computer.
Typically, the wireless LAN card requires an antenna for wireless communication. The antenna is smaller than the wireless LAN card or a ground provided in a portable computer. Beams emitted from an antenna are radiated toward a ground. Electromagnetic waves leak from the ground, and the average gain of the antenna drops, so antenna efficiency is diminished. If the antenna receives a large amount of power, the beams distributed toward the ground may not disrupt data communication. However, if the antenna receives a small amount of power, it is difficult for a portable computer to efficiently communicate with an external apparatus.